Kollon

The game is a connect-the-colors block game, much like Nintendo's Pokemon Puzzle League (which, in turn, was based on another game whose name escapes us at the moment), but Kollon's little twist on the formula is a good one. Instead of swapping a row of two blocks at a time to connect colors, Kollon has a four-block square to twist blocks left or right. The neat thing about this arrangement is the number of options it presents -- if you have a precariously-built stack of blocks, you can swap blocks off the edge to have them drop down on the blocks below. Also, if you're fast, you can defy gravity by spinning the square 180 or 270 so that the blocks you've spun are still in their original spot before they fall (very handy for dropping blocks out of the middle of towers to make combos).